Gov. Tom Vilsack of Iowa announced yesterday that he would restore voting rights for all felons who have completed their sentences, ending what advocates for voting rights had called one of the most restrictive disenfranchisement laws in the country.

The governor's order, which he plans to sign on July 4, will make an estimated 80,000 ex-felons eligible to vote. Advocates hope that the order, which comes after a similar restoration of voting rights in Nebraska, will encourage other states with similarly restrictive laws to broaden voting privileges for ex-felons.

Nationally, about 4.7 million people are ineligible to vote because of felony convictions, about 500,000 of them war veterans, according to the Sentencing Project, a nonprofit organization that promotes alternatives to incarceration. About 1.4 million are black men.

President Bush and other politicians have emphasized the importance of smoothing prisoners' re-entry into society, and advocates say granting ex-felons the right to vote is an important part of encouraging them to be law-abiding citizens.

Mr. Vilsack, a Democrat who has been called a dark-horse presidential candidate for the 2008 election, pointed to research showing that ex-prisoners who vote are less likely to end up back in prison.

"When you've paid your debt to society, you need to be reconnected and re-engaged to society," Mr. Vilsack said yesterday at a news conference, where he was joined by Democratic and Republican legislators who had pushed for the change.

Every state but Maine and Vermont prohibits felons from voting for some period after their convictions, but the states vary in how and when they restore voting privileges.

According to the Right to Vote Campaign, which works to reverse laws preventing felons from voting, 14 states automatically restore voting rights to felons after they are released from prison; four states restore rights after ex-felons complete parole; and 18 states do so after they complete their prison sentence, parole and probation.

Iowa is one of five states - the others are Kentucky, Alabama, Florida and Virginia - that deny a vote to anyone convicted of a felony or an aggravated misdemeanor.

Felons wanting to vote in Iowa have had to petition the governor's office, which then forwards the application to the State Division of Criminal Investigation, which in turn sends it to the parole board for a recommendation, typically up to a six-month procedure.

Mr. Vilsack said that about 600 ex-felons petitioned for voting rights last year, and after he signs the executive order, about that many will be restored to the voting rolls each month. The department of corrections will be responsible for submitting to the governor's office each month's list of eligible ex-felons: people who have completed their sentences, probation and parole.

The law in Iowa has disproportionately affected minority voters; 19 percent of those denied the vote are black, even though blacks make up only 2 percent of the state's population.

"This is a huge victory for voting rights and for civil rights," said Catherine Weiss, associate counsel at the Brennan Center for Justice at New York University Law School, which has sued to overturn Florida's ban on voting by ex-felons.

Nebraska and Iowa, Ms. Weiss noted, were the last two states outside the South to overturn their bans. "Once Nebraska went, the pressure on Iowa increased dramatically," she said.

Across the country, advocates have filed lawsuits to expand voting rights; next week, Ms. Weiss said, the United States Court of Appeals for the Second Circuit will consider whether New York's law, which denies the vote to felons on parole, violates the Voting Rights Act because it disproportionately affects blacks and Hispanics.

Ryan King, a research associate at the Sentencing Project, said that about one million ex-felons, including 600,000 in Florida alone, would be eligible to vote if the four states with laws similar to Iowa's granted voting rights to ex-felons.

"The governor's choice of doing this on July 4 is very symbolic," Mr. King said. "It's a celebration of democracy."

Iowa has a significant role in the presidential primary season. But Debra Breuklander, an ex-felon who appeared with the governor at his press conference, said that Mr. Vilsack's action went beyond politics.

"I have children that are still in school; I have a grandson that will be going to school," said Ms. Breuklander, 46, who was released from prison in June 2003 after serving time on a conviction for conspiracy to distribute methamphetamine and who now works as a nurse at a drug treatment center. "Not even to be able to have a say-so in what goes on in the schools was driving me crazy."

She added, "If nobody hires you and you don't feel like you're a part of anything, all you will do is feel like you may as well go back to what you know, which is the drugs."